Variable Valve Lift Connecting Structure Alignment
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Solution Overview
Problem
Existing variable valve lift apparatuses face challenges in accurately controlling the position of cam lobes relative to the camshaft, leading to inefficient valve operation and potential interference among components, which affects engine performance.
Innovation Solution
A variable valve lift apparatus with a connecting structure that includes first and second cam forming portions, moving units, actuating units, a positioning unit, and a stopper unit, utilizing a pin actuating device and a linking unit to move in the shaft direction of the camshaft, allowing for precise alignment and reduced interference between components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable valve lift apparatus is designed to vary the relative position of cam lobes to the camshaft, then valve operation can be optimized for different engine RPM, but the control precision of cam lobes becomes difficult to maintain
Solution Approach 1:
A positioning unit is introduced as an intermediary component between the camshaft and the cam lobes. This positioning unit includes positioning pins that selectively engage with positioning holes in the cam forming portions, serving as a mediator to precisely control and maintain the relative positions of cam lobes while allowing for variable valve lift operation at different engine RPM
2Adaptability or versatility
If multiple cam forming portions are used to control valve operation, then valve lift can be varied, but interference among components increases
Solution Approach 1:
The camshaft assembly is segmented into multiple independent cam forming portions (first and second cam forming portions), each capable of being selectively positioned. The positioning unit divides the control function into separate positioning pins that can independently engage with positioning holes, allowing each cam lobe to be controlled separately and preventing interference between adjacent components during variable valve lift operation
3Measurement precision
If a complex connecting structure is used to position cam lobes, then position control improves, but device complexity increases
Solution Approach 1:
The positioning function is extracted as a separate, dedicated positioning unit that operates independently from the main camshaft and valve train components. This positioning unit with its simple positioning pins and positioning holes provides precise cam lobe position control without adding complex mechanisms to the overall engine structure, thereby maintaining device simplicity while achieving accurate positioning
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient actuation with a simplified design, reduces the number of solenoids needed, and minimizes positional deviations, improving spatial utilization and manufacturing efficiency while maintaining precise valve operation.
Implementation Method 1
a stopper body elastically supported on the compression spring and selectively inserted into the first and second grooves
Data Source
AI summary
A variable valve lift apparatus that has a simplified configuration is provided. The apparatus includes a camshaft and first and second cam forming portions inserted with the cam shaft to rotate together with the camshaft and be movable in a shaft direction of the camshaft, and includes an upper cam and a lower cam. A valve opening/closing device is actuated by the upper cam or the lower cam. First and second moving units are inserted with the camshaft and are movable together with the cam forming portions. First and second actuating units selectively move the moving units in the shaft direction of the camshaft and are mounted on a mounting portion. A positioning unit is connected with the moving units, and has first and second grooves. A stopper unit is mounted on the mounting portion, and is selectively inserted into the grooves to align the cam forming portions.